Simulation Research On Damage Law Of Hard Object To The Engine Fan Blade

In the foreign object damage research of the engine fan blade, in order to obtain the data of the first hit between the hard object and the fan blade with the depth and width of the dent caused by the impact. Motion trajectory of hard object under different initial conditions in the engine flow field starting from the ground to the initial impact to the fan blade could be obtained with the impact position, the velocity and the impact direction of hard object to the engine fan blade by means of Computational Fluid Dynamics. Collision model would be established in order to simulate the dent depth and width that hard object under different initial conditions impact the inlet edge of fan blade, and the size dent would be used to provide the theory foundation for damage identification and test of aircraft engine fan blade.The specific research method was as follows:(1) Differential equation of hard object motion was established by analyzing the physical properties and the stress in the flow field of hard object according to the Newton's second law.The iteration formula of the position coordinates of the hard object in the flow field was obtained by the integral. The entire trajectory of the hard object would be determined According to repeated calculation of the iteration formula and the aerodynamic parameters of any point in the flow field. Estimating the velocity of the hard object impact fan blade, and the velocity estimation value of the hard object impact fan blade was obtained.(2) 3-dimensional geometric model of the engine fan blade with a fairing and the air flow field model which was inhaled by the engine was established. The flow field simulation through which the air flow field simulation model has been completed through which the air flow field simulation model was established and the simulation of the trajectory of hard object in the flow field has also been finished by using particle discrete phase model. Different trajectory charts of hard object in the flow field could be obtained with the impact position,the velocity and the direction of hard object to the engine fan blade according to the different initial conditions of hard object.(3) A large number of impact simulations would be carried out after calculation model of hard object impact the fan blade was established and the material parameters were determined.The relationship between the damage dent size that hard object impact engine fan blade inlet edge and velocity, diameter, density, and location of the hard object was analyzed.The simulation results indicated that the hard object inhaled by the engine was almost in the same zone when it arrived the intake port even though the hard object started from very different positions,in addition impact positions were mostly found below the center line of the YOZ cross blade tip section. There was a nonlinear proportional relationship with the dent size in blade inlet edge after hard object impacted the fan blade and the increase of velocity,diameter and density of hard object. The simulation results provided theoretical basis for the damage test of aircraft engine fan blade.